1. Field of the Invention
The present invention relates to a construction machine, such as a hydraulic shovel, having a muffler mounting device for mounting a muffler used in an engine exhaust system, in an engine room.
2. Description of the Related Art
A hydraulic shovel will be taken as an example to describe the background art.
FIG. 6 shows an upper rotating body mounted on a lower traveling body. In the figure, reference numeral 1 denotes an upper frame of the upper rotating body. At one end (at the left side end in the figure, the side of this end will hereinafter be referred to as front) of the upper frame 1, a working attachment (not shown) including a boom, an arm, and a bucket is attached.
On the upper surface of the upper frame 1, on both sides of the middle portion in the left-right direction and over substantially the entire length in the front-rear direction, longitudinal plates (also referred to as main frames) 2 and 3 serving as strength members are provided, and in the rear, partition walls 4 to 6 extending in the left-right direction are provided. At the rear end of the upper frame divided by the partition walls 4 to 6, an engine room 7 is formed.
In the engine room 7, an engine 8 is provided between the left and right longitudinal plates 2 and 3, and on the left side of the engine 8, a cooling fan 9 and a heat exchanger 10, such as an intercooler, a radiator, or an oil cooler, are provided as a cooling installation.
On the right side of the engine 8, a hydraulic pump 11 is provided so as to be connected to the output shaft of the engine, and a muffler 12 is placed over the hydraulic pump 11.
In a conventional muffler mounting device, as shown in FIG. 7, a muffler mount 13 projects from the pump side surface of the engine 8, and the muffler 12 is placed on the muffler mount 13 and is secured with a U-shape bolt 14 (see Japanese Unexamined Patent Application Publication Nos. 2003-104071 and 10-317957).
The inlet side (the engine side) of the muffler 12 is connected to an engine exhaust pipe through an accordion-pleated bellows for absorbing the relative displacement of the engine 8 and the muffler 12 due to vibration. During assembly (when the muffler and the exhaust pipe are connected), some assembly errors including that in the axial direction of the bellows can be absorbed by the deformation of the bellows.
However, in this art, the bellows is the only device for absorbing assembly errors. Therefore, the only way to absorb errors beyond the adjusting capability of the bellows is to enhance the adjusting capability by lengthening the bellows. This leads to higher cost.
In addition, the bellows is formed of metal and a substantial force is needed to deform it. Therefore, the position adjusting operation relative to the exhaust pipe is troublesome.